Rolls of toilet paper and paper toweling typically comprise a paper product wound upon a hollow core. The roll is typically supported for rotation on a spindle which extends through the hollow core.
A typical core shape for dispensing a paper product is a cylinder having a geometrically circular cross-section. A core with a circular cross-section freely rotates about the axis of the spindle and permits smooth dispensing of the paper product from the roll. However, a core having a hollow circular cross-section has a relatively large void space. It is desirable to reduce such void spaces to improve shipping and storage efficiencies.
One improvement to core wound paper products includes diametric compression of the roll, such that the core has a generally flattened configuration with reduced core void space. The flattened core configuration permits the core wound product to be shipped and stored more economically and in higher densities.
Several attempts have been made in the art to realize the benefits of compressed core wound paper products. Examples of compressed core wound paper products are disclosed in the following references: U.S. Pat. 401,233 issued Apr. 9, 1889, to Wheeler, U.S. Pat. 972,668 issued Oct. 11, 1910, to Wheeler; U.S. Pat. No. 1,005,787 issued Oct. 10, 1911, to Sibley; U.S. Pat. No. 4,762,061 issued Aug. 9, 1988, to Watanabe, U.S. Pat. No. 4,886,167 issued Dec. 12, 1989, to Dearwester, U.S. Pat. No. 4,909,388 issued Mar. 20, 1990, to Watanabe, U.S. Pat. No. 5,027,582 issued Jul. 2, 1991 to Dearwester; PCT International Publication Number WO 92/11196 Published Jul. 9, 1992, by Dearwester et al.; and G.B. Patent 709,363 issued May 19, 1954, to Samson.
While the compressed rolls taught in these references reduce hollow core void space, they do not provide preferred dispensing characteristics. Previously compressed or flattened cores, when rerounded, typically have a non-circular cross-section. Flattening of the core for compression creates generally flattened core sections connected at folding creases or vertices. The rerounded core will have an oblong or polygonal cross-section having a relatively flat side corresponding to each folding crease or vertex. Such a core cross-section is characterized by nonuniform radial clearances between the core and spindle at different circumferential positions on the core. These differences in radial clearance result in wobble and noise as the roll is rotated on the spindle to dispense the paper product.
Accordingly, it is an object of the present invention to provide a core which has a generally flattened configuration and a generally rerounded configuration. Another object of the present invention is to provide a core having a means for reducing the clearance between the core and the spindle when the core is in the generally rerounded configuration. Yet another object of the present invention is to provide a core having a portion that can be deformed to extend radially inwardly to reduce core to spindle clearance when the core is in the generally rerounded configuration. Yet another object of the present invention is to provide a core having a portion that can be deformed to extend radially inward to engage a spindle, so that the spindle and core rotate together during dispensing of a paper product.